Research

Constraints on Martian Core from First Observations of SKS Waves

Mars has a liquid iron alloy core at its center. Using seismic data gathered by the InSight mission, we have made the first observations of seismic waves traveling through Mars’ core. We use the travel times of core-transiting seismic waves, relative to ones which remain in the mantle, to constrain properties of the core and …

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Spurious Low Velocity Zones in Joint Inversions of Surface Waves and Receiver Functions

Low-velocity layers within the crust can indicate the presence of melt and lithologic differences with implications for crustal composition and formation. Seismic wave conversions and reverberations across the base of the crust or intracrustal discontinuities, analysed using the receiver function method, can be used to constrain crustal layering. This is commonly accomplished by inverting receiver …

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Improved Model of Outer Core 1D Structure

We have published a new model of 1D structure of the outer core, parameterized using two different equations of state: Irving_Cottaar_Lekic_2018 Brief highlights: We infer the seismic properties and equation of state of the outer core using Earth’s oscillations We address a longstanding discrepancy between high and low frequency investigations of the outer core Our work …

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Quaking the Delaware

Graduate students at the University of Maryland Seismology Lab sprung into action following the M4.1 earthquake that struck Dover, Delaware on November 30, 2017. The very next day, they were out in the field, deploying seismometers that would be recording aftershocks for the next 6 weeks. Thank you Erin, Chao, Phillip, Karen, Pete, and Quancheng …

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Things to consider when interpreting Sp receiver functions…

Conversions of shear waves (S) to compressional waves (P), often analyzed as Sp receiver functions, are useful for studying upper mantle layering, and have been used to map upper mantle seismic impedance interfaces in various tectonic settings. Recently, common conversion point stacking of Sp receiver functions has revealed variations of lithospheric thickness across short horizontal …

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About those amplitudes…

It is well known, at least among tomographers, that our images of the Earth’s interior are washed out. Lateral variations in seismic velocities are likely to be weaker in our models than in the actual Earth due to explicit and implicit regularization needed to obtain a solution to our mixed-determined inverse problems. As a result, …

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3D Reference Earth Model

REM-3D is a project funded by the National Science Foundation and carried out by Raj Moulik, Ved Lekic, Barbara Romanowicz, and Adam Dziewonski. If you have questions, please do not hesitate to contact us. You might find the answer you are looking for in our new FAQ section. The aim of the project is to develop a three-dimensional …

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